A. IVANOVA and N. TSENOV
Dobrudzha Agricultural Institute, BG - 9520 General Toshevo, Bulgaria
IVANOVA, A. and N. TSENOV, 2012. Winter wheat productivity under favorable and drought environments. II. Effect of previous crop. Bulg. J. Agric. Sci., 18: 29-35
During the growth period of field crops, drought (both short and long lasting) is becoming increasingly frequent. Drought is an abiotic stress factor of the environment, which reduces the yield from cereals worldwide. The effect of different previous crops on the productivity of common winter wheat genotypes was investigated under favor-able and drought environments. The investigated cultivars were grown in two successive years - 2006, which was very favorable for wheat growth, and 2007 when one of the severest and longest droughts in Bulgaria occurred. The genotypes were grown after four previous crops (bean, sunflower, grain maize and fodder maize) at three levels of mineral fertilization according to the type of previous crop. Grain yield and the productivity components were studied: 1000 kernel weight, test weight, number of productive tillers, plant height, number and weight of grains per spike. The correlations of grain yield with the traits related to it were analyzed after different previous crops under contrasting conditions of the environment. A marked positive role of bean as previous crop under drought condi-tions was established. Bean decreased with only about 9% the productivity of the wheat genotypes grown after it. The high negative effect of sunflower and grain maize was stronger under drought. The productivity of the wheat genotypes grown after these two predecessors dropped down with 22-25%. Fodder maize had an intermediate ef-fect. The cultivars grown after it decreased their productivity with about 21%, but it was the best predecessor for formation of 1000 kernel weight. Regardless of the year conditions, correlations of grain yield with its components were inversely proportionate to the “good” predecessors.